Airplane skid



F. S. COTTON AIRELANE SKID Dec. 9, 1930.,

Filed Oct. 18, 1926 Patented Dec. 9, 1930 UNITED STATI-:s

PATENT OFFICE.

AIRPLAN E SKID Application led October 18, 1926. Serial No. 142,303.

This invention relates to airplanes, and more particularly to airplane skids for use in taking olf from, or landing on, snow.

Polar regions and snow covered ground have offered peculiar difculties to the taking off, and landing of airplanes. Thus, in landing, the skids have frequently broken off and in other cases have sunk sutliciently deeply into the snow to suddenly retard the forward progress of the plane to cause the machine to turn on its nose. Moreover, in traveling over the snow in taking 0E, the weight of the plane exerted on the snow through the skids has caused the skids to sink into the snow sufficiently to make difficult the rising of the plane into the air. Furthermore, particularly near the salt water which renders the snow sticky, the snow has adhered to the skids in such manner as to greatly impair the eliciency thereof. Moreover, salt water impregnated snow causes a heavy friction, inaking it diicult for an airplane to rise from such snow.

An object of this invention is to provide air plane skids of such character that saidv skids may ride readily on the surface of snow.

Another object of my invention is to mount skids on airplanes for use on snow, whereby an airplane may readily travel on the surface of uneven stretches 'of snow.

A further object of the invention is to provide flexible landing skids for airplanes, whereby said airplanes may readily travel over uneven frozen surfaces.

Another object of my invention is to provide airplane skids which will not adhere to soft or sticky snow to retard the progress of theI airplane.

Other objects of the invention will be apparent to those skilled in the art from the description of it hereinafter given.

In the drawings, Figure 1 is a side elevation of an airplane provided with skids contemplated by my invention.

Fig. 2 is a fragmentary front elevation of the airplane shown in Fig. 1.

Fig. 3 is a top plan view of a skid of my invention.

Fig. 4 is a longitudinally vertical section through my improved skid showing the means for attaching the skid to the airplane.

Fig. 5 is a transverse vertical section taken on line 5-5 of Fig. 4.

My invention contemplates advantageous airplane landing gear for use particularly on snow or similar frozen surfaces. I have found that flexible skids are particularly advantageous on snow and more particularly where the surface of the snow is uneven. have furthermore found that with skids having a concave under surface, the weight of the airplane may be readily borne by the skids without causing the skids to sing appreciably in the snow. Where sticky snow is encountered, as near the salt water, such snow may be prevented from adhering to the skid by covering the lower and side surfaces thereof with a thin layer of sheet metal, such for example, as brass, aluminum, or duralumin.

Moreover, I have discovered that the travel of an airplane on snowy surfaces, or the landing of an airplane on such snow, may be rendered considerably easier by causing the portion of the weight of the airplane carried by its skid to fall on the rearward portion thereof. Preferably, the weight falls on the skid not more than three-eighths of the distance from the rear end toward the front end of the skid. By this construction, the rear portion of the skid carries most of the weight, permitting the front portion thereof to mount obstacles and negotiate depressions and rises in the ground more easily.

There is illustrated in the drawings an airplane l of usual type having a front landing gear axle 2 and a rear drag or tail skid 3. Each connecting means designated generally by 4 is secured at its upper portion to the axle 2 and at its lower portion to the skid 5. Each front skid 5 is shown as comprising a relatively long and narrow flexible portion 6 upturned at its forward end 7. The flexible portion 6 may be composed of any suitable material such as ash or hickory and may be solid or laminated as shown in Figs. 4 and 5. The ends of the skid are relatively thin and the portion of the skid adjacent the attaching or connecting means 4 somewhat thicker.

Iso

Preferably, to prevent sticky snow and the like from adhering to the flexible portion 6, and to prevent friction with sticky snow, a metal sheath 8 may be disposed on the bottom and sides of the skid and may extend partially over the top thereof. In certain cases, of course, the skid might be entirely enclosed within a metal sheat The sheath 8 is preferably thin so as not to reduce appreciably the pliability of the skid, and may be composed of any suit-able material, such as brass. Other materials, such as aluminum,

duralumin or steel, may also be employed for this purpose. By thus covering the lower and side portions of the skid with suitable sheet metal the skid may be ke )t substantially free from adherent snow; lMoreover, by such sheathing the life of the skid is prolonged.

0n the upper surface of each skid 5 are secured a plurality of brackets 9 to which the legs 10 of the supporting means 4 are secured by means of pins 11. Secured to the upper portion of the legs 10 is the collar 12, which is adapted to be disposed around the axle 2 and to be maintained in position on the axle by a suitable pin 13 or similar fastening means. The collar, which is capable of pivotal lmovement on the axle 2, may be formed integral with the legs 10. To render the supporting means more rigid, cross bracing wires 1.4 may be attached to the legs 10 and collar 12 transversely of the supporting means 4, as shown in Fig. 2. The supporting means 4 are so disposed that the center of the load exerted on the skid 5 falls on the rearward portion thereof. ample, referring particularly to Fig. 4, the distance measured parallel to the skid from the rear end of the skid to the center of the axle 2 is preferably not more than threeeighths of the entire length of the skid measured parallel to the skid.

Forwardly of the connecting means 4 are shown resilient skid positioning members 15 and 16 secured at one end to each skid 5 and at the other end to the fuselage, which members, during iight, serve to keep the forward ends of the skids in line for landing and to prevent said skids from pointing downwardly, due to wind pressure. 'lhe members 15 and 16 may be advantageously composed of the type of elastic employed in airplane shock absorbers. A cable 17 and shackle or turnbuckle 18 are shown secured to the rear end of each skid and to the fuselage, the purpose of said cable and turnbuckle being to keep the skids level with the line of flight and to keep the skids in position for landing. The cable 17 and turnbuckle 18 moreover prevent the machine from turning on its nose in the event of the airplane coming to too abrupt a halt on landing. The turnbuckles 18 permit the adjustment of the cables 17, to adj ust both skids 5 to the same level, so that one Thus, for exskid will not point up or down more than the other.

It will be understood, of course, that any equivalent means might be employed to hold the skids in desired position. Thus, for example, collapsible legs (not shown?i might be attached to the rear end of each s id and to the fuselage to maintain the skids in proper position.

A snow skid 5a, similar to but proportionately smaller than the skids is shown secured to the tail skid 3 of the machine to prevent thetail end of the -machine from sinking in the snow. The skid 5a is shown as comprising a flexible portion 6a, and is secured to the tail vskid 3 by securing means 4a similar to the securing means 4. Skid positioning members 15a!I and 16a, cable 17 a and turnbuckle 18a are similar to the corresponding members 15, 16, 17 and 18 and perform the same functions.

With my improved skids secured in the above mentioned relation to an airplane, taking off from and landin on snow covered ground is made easy and ree from danger of damage to .the machine. Thus, the concave under surfaces of the skids collect the snow into narrow-treads and harden the snow, preventing the machine from sinking therein. For the same reason, the skids are prevented from sinkin into the snow when making a sharp turn. gDue to the flexible nature-of the skid, uneven ground may be readily traversed without danger ofv the front end thereof pointing into the ground and causing the ma- Cil chine to turn on its nose. Moreover, by causl ing the weight of the machine to rest on the rearward portions of the skids, the front ends thereof may readily rise to mount obstacles. In the event of the machine meeting a rise in the ground, the rear portions, by having 'the weight concentrated thereon, are force-d down and the front portions readily rise to negotiate said rise. Likewise, when meeting a depression inthe snow, the forward portion of the skid rides into the depression, during which time the weight of the plane is thrown forward onto the portion of the skid in the depression, causing the point of the skid to flex upwardly to a considerable degree, as a result whereof the skid as a whole rides easily into and vout of the depression.

It will be noted that by the use of the ilexible skids disclosed herein, a maximum contact of the skids'with the snow is obtained even though the surface of said snow be rough and uneven. As a result, the take-off may be made in a shorter time and ina shorter space than possible with a rigid skid having, of course, a much less possible area of contact with the snow.

It will thus be seen that I have provided advantageous landing gear for airplanes, whereby said airplanes may readily take off from, or land on, snow covered ground.

Furthermore, it is to be understood that the particular forms of apparatus shown and described, and the particular procedure set forth, are presented for purposes of explanation and illustration and that various mrdifications of said apparatus and proce u my invention as defined in the appende claims. Y

Wlat I claim is:

l. in combination with an airplane, landing gear comprising a plurality of relatively long and narrow flexible skids, said skids having transversely concave under surfaces,

said skids being attached to the airplane so that the load to be carried by each skid will fall on the rearward portion thereof, whereby said skids may ride `readily upon the surface of snowV and may readily negotiate uneven surfaces. 4

2. ln combination with an airplane, landing gear comprising a plurality of relatively long and narrow flexible skids, said skids being att-ached to the airplane so that the load to be carried by each skid will fall on the rearward portion thereof, not more than three-eighths of the distance from the rear end toward the front end thereof, whereby the rearward portion of the skids will carry the greater proportion of the weight'thereof and whereby said airplane may readily negotiateA uneven, snowy surfaces without tions,

appreciable danger of tipping on its nose.

3. In an airplane skid for use on snow, a relatively long, narrow flexible member having a transversely concave under surface, and metal sheathing on the under and side surfaces of said skid, whereby to substantially prevent friction with snow and adherence of snow to said skid.

4. fn askid for use on snow, and adapted to be attachedto an airplane by attaching means, a relatively long and. narrow flexible member of superimposed wooden laminasaid member being relatively thin adjacent its ends and thicker adjacent said airplane attaching means, a transversely concave under surface extending substantially the entire length of said skid, and a metal sheath covering the under and side surfaces of said skid, whereby said skid may ride readily upon the surface of snow without substantial adherence of snow thereto.

5. n combination with an airplane, landing gear comprising a plurality of relatively long and narrow flexible skids arranged to conform substantially to the contour of the ground being traversed, said skids being at- .I tached to the airplane so that the load to be carried by each skid will fall onthe rearward portion thereof whereby said airplane may readily negotiate uneven surfaces without appreciable danger of tipping on its 1 nose. and means for maintaining said skids he can be made,without departing fromv d therebeneath and thus rlde read11y upon the ing gear the surface of snow,

member, the under surface of said member being transversely concave, whereby said skid may compact and compress the snow surface ofthe snow.

7. In .an airplane skid for use on snow, a relatively long and narrow flexible member arranged to conform substantially to the contour of the ground being traversed, the under surface of said skid being provided with a metal sheath to prevent snow from adhering thereto, said sheath being suficiently thin as not to aect substantially the flexibility of said skid.

8. In combination with an airplane, landcomprising a plurality of relatively long and flexible skids, the under surface of each said skid being transversely concave throughout substantially its entire length, whereby said skids may support relatively heavy weights and yet ride readily upon the surface of snow, even when the surface of said snow is rough and uneven.

9. In combination with an airplane, landing gear comprising a plurality of relatively long skids of sucient bottom surface area ing gear compr1s1ng aplurality of relatively long skids of suicient bottom surface area to support the weight of said airplane on the under surface of each skid being transversely concave throughout substantially its entire length, whereby to increase the buoyancy of said skids on snowy ground, said skids being sufficiently flexible to conform to the contour of the snowy ground caterpillar fashion When said airplane is in motion on the ground, the under surfaces of said skids being covered with sheet metal of a class comprising brass, aluminum or duralumin sufciently thin so as not appreciably to reduce the flexibility of said skids.

In testimony whereof, I hereunto afiix my signature.

rnnnnaioxsmunr Gorros'. 

